US Census Bureau
U.s. Census Bureau: Poverty
The U.S. Census Bureau offers the official statistics on poverty.
University of Wisconsin
Institute for Research on Poverty: How Is Poverty Measured in the United States?
Describes how the United States measures poverty. Includes graphs comparing poverty rates over time, in different states, in different ethnic or age groups, etc.
Other
Us Health & Human Services: Poverty Guidelines, Research, and Measurement
This site from the U.S. Department of Health & Human Services provides resources on both poverty threshold and poverty guidelines, and describes how they are used by federal programs for setting eligibility criteria.
Other
Health & Human Services: Development and History of u.s. Poverty Thresholds
A review of the development and history of the current, official poverty thresholds.
NPR: National Public Radio
Npr: Welfare Reform in America
The federal welfare reform act has been in existence from 1996. This article, dated 3/2004, looks at how we are doing. What is the state of welfare reform -- has it helped or hurt the situation.